Finding answers about our world

The grassy plains of Sahara

Sahara desert used to be green. 9,000,000 square kilometers of sand and rocks - that's what the Sahara desert is. Second only in lifelessness to the Antarctica. To better understand it's size, imagine this - it's larger than Australia. And as if that wasn't enough, the Sahara is expanding! By approximately 48 kilometers per year, towards the south, the tropical savannas. But the desert isn't as lifeless as it may seem. Many species of animals live by the Nile, which is the heart of Sahara. Other than that, only occasional oases can offer some kind of refuge from the ruthless desert. But when did all these oases appear? Here's the catch - Sahara wasn't always a desert. In fact, around 120 000 years ago, the desert was thriving.

Rivers ran through the desert and grassy plains loomed along them, probably housing thousands of species of various critters. But how was all of this found out? Scientists from MARUM – Center for Marine Environmental Research in Bremen and the Alfred-Wegener-Institute in Bremerhaven, were studying the coast of northwest Africa, hoping to find out how the hydrological cycle changed over the years. Over the last 120 000 years, there were three periods of particular interest. During these periods, particles of the land were transported by water and not by wind, as it is usual in the desert. This lead the scientists to think that once rivers were flowing through the Sahara. Computer simulation proved this, showing three periods of Sahara having almost full grass coverage. Besides, it calculated that only a minimal increase of the Sahara's current 2 to 10 centimeters of rain per year would be sufficient to cover the desert with grass.

It is not known whether Sahara will ever be green again. And I'm sure scientists know more than me, but couldn't have those particles been brought by a really huge tsunami, rather than a river? One thing is certain, though. If Sahara was grassy, it would soon be exploited and the world food prices would decrease, putting an end to global hunger... i think.

Our oceans are not soaking up as much CO2 as we'd like to

The sea has always captured the imagination of all people. Neither has it shown mercy to the brave people that dared to traverse it and claimed many lives. Luckily, our oceans also claim a lot of carbon dioxide, helping keep the air we breathe fresh. Not as efficiently as we'd like, though.

I assume we all know by now that too much carbon dioxide is hovering in our atmosphere, and the pollution levels continue to grow. But, man has to understand, that not everything is within his power. The various flora of our world soak up the carbon dioxide and produce oxygen. This process is know as photosynthesis. But did you know that most of the carbon dioxide is absorbed by oceans? Firstly, it is used by plankton for photosynthesis, and secondly, it simply dissolves in water as most gases should. Carbon dioxide molecules are heavier than water, so the gas slowly makes its way down to the depths. Add the dead fish and plankton to that, incredible pressure from the water above, and after millions of years of anaerobic decomposition, and you'll get oil!

The main point is that the deep seas are CO2-heavy. But thanks to the already undergoing climate changes, the winds above seas increase, thus causing considerable water mixture in the seas. That means that deep water comes up, bringing all the carbon dioxide with it. Although it will not exactly make it's way back to the atmosphere, the surface waters mix with the deep ones, thus the surface waters will have more carbon dioxide in them and less from the atmosphere can dissolve in them. This phenomenon actually decreased the absorbing capability of 0.5 Gigatonnes per year, to almost 10 times less, 0.05 Gt/y. (Research was conducted in the Southern ocean.)

The study has been conducted over a 10 year period, so the numbers really shouldn't lie. As you see, the ammount of carbon dioxide people produce is not as big as there is already circulating in nature, but that doesn't mean that we should cut down on emissions. After all, it may have been human pollution that caused the weather change. One event leads to another, so let's wait and see.

New animal species discovered

Noblella pygmaea is the name given to a recently discovered frog, which would barely fit on your fingertip. This, averagely reaching a length of 11.4 millimeters, amphibian has until now evaded human sight. However, a german herpetologist Edgar Lehr and Swiss-Peruvian ecologist Alessandro Catenazzi managed to spot this unique frog during field work.

This picture, emphasizing the frog's size was taken by A. Catenazzi. This creature is obviously very well adapted to it's environment, as can be seen from it's size and brown camouflage. But what exactly is it's environment? That would be the the lowland rainforests of the Andes. This particular discovery was made in the Manu National park. The amphibian lives in altitudes above 3000 meters, a height where most species of animals are larger than in near sea-level areas. So this frog was quite a surprise. This discovery might encourage future explorers to delve deeper into the mysteries of rainforests.